Hikers beware, the start (and end) of this trail are brutal.
With Holy Jim closed, this seems to be the best way up to Santiago Peak but I'm still on the fence about if it was worth it.
Two main things to be aware of.
First, the majority of the trail is shared with mountain bikers who don't wear bells so you need to be ready to dive into the hedges when they come flying around a corner.
I was pretty lucky that there were only a handful on the trail that day and I encountered them in spots where I could hear them coming and get out of the way with too much issue.
Second, the first leg up to Old Camp is brutal on the way up and honestly worse on the way back down.
I got greedy and decided to bag Modjeska peak while I was up there and that meant I caught the last 2 miles of the trail during sunset.
Even if I had the sunlight though, man was it a miserable descent.
It's not as noticeable on the ascent but the trail is really slippery in a number of spots.
It's also very steep. Like bring a trekking pole even if you hate them steep.

Also worth noting is that the sign has been stolen/knocked down so there's no perfect indicator of the peak.
If you follow the 4 wheelers all the way though, there's a nice scenic spot to have lunch and rest for the return hike back I'd definitely recommend.
There's also a shady spot under a tree near one of the towers but the whine was so loud it wasn't worth spending too much time on.
Try to plan for Modjeska peak too, it's really close and much more satisfying to summit since there's no giant antennae buzzing over your head and a stunning view.
Just, don't be like me and make sure to start early enough that you're not trudging down in the dark singing loudly to scare off any mountain lions by the light of a headlamp.